1. Field of the Invention
The present invention relates to protein-bound magnetic particles and a production method thereof, as well as a novel gene, gene fragment, fusion DNA sequence, recombinant plasmid, and transformed magnetic bacterium.
2. Description of the Prior Art
Proteins having biological activities such as enzymes and antibodies immobilized on magnetic particles can be led by magnetic means. Therefore, they can be led to local positions at which it has been hitherto difficult to arrive. Further, they can be collected and separated by using a magnetic force. Thus they are expected to be utilized in various industries including the fields of medicine and fermentation.
In the prior art, for example, immobilization of biologically active substances to magnetic particles is disclosed in Japanese Patent Publication (KOKOKU) No. 6-12994. Namely, magnetic particles are separated from a magnetic bacterium by an alkaline treatment, and they are treated with .gamma.-aminopropyltriethoxysilane or glutaraldehyde, to which a biologically active substance is chemically immobilized. A method is also known, in which magnetic particles are separated by an enzyme treatment from a magnetic bacterium in a state of being covered with an organic thin membrane comprising lipid, and a protein is immobilized thereto after a treatment with glutaraldehyde. A method is also known, in which a biologically active substance is immobilized on magnetic particles by a chemical binding method by using SPDP (Japanese Pre-examination Patent Publication (KOKAI) No. 5-209884).
Further, methods for measuring antigens or antibodies have been proposed, in which an antigen-antibody reaction is performed by using the magnetic particles to which a biologically active substance is chemically immobilized by the aforementioned methods (Japanese Pre-examination Patent Publication (KOKAI) Nos. 4-285857, 5-209884, and 5-99926).
However, in any of the foregoing, it is necessary for a protein such as an enzyme, or an antibody, etc. to be chemically bound to magnetic particles. Thus problems have arisen in that a long period of time is required for the immobilization treatment, that the biological activity of the protein is deteriorated due to the immobilization treatment, that the amount of obtained immobilized protein is greatly dispersed among lots, that the activity is also greatly dispersed, and that the immobilized protein inevitably becomes expensive because the protein to be used for immobilization is generally expensive.